text: Using the continuity equation and the fact that the tangential velocity component does not change across the shock, trigonometric relations eventually lead to the θ-β-M equation which shows θ as a function of M, β and ɣ, where ɣ is the Heat capacity ratio.
  It is more intuitive to want to solve for β as a function of M and θ, but this approach is more complicated, the results of which are often contained in tables or calculated through a numerical method.